If you want to try something that's super fast and works beautifully, with no wear at all to the cloth, I use an Evercare pet hair roller. It's a 10" peel-able hair and lint roller shaped like a paint roller. I can do my 9' table in about 15 seconds and it picks up all the chalk, everything. You just peel for a new sticky surface and continue.
Vacuum cleaners work well but they're slow. Brushing grinds dust in and creates too much dust. Wiping with a damp cloth doesn't pick up everything. These things pick up everything with a few swipes - like it was made for a pool table. I orginally got these to remove cat hair (we have two pet Bengals) from a velvet couch - then I realized they were perfect for pool tables.
For commercial use, I would do it at least a couple of days a week, but it's so fast you can probably do all the tables in 10 - 15 minutes if you want to do them nightly. You can brush the underside of the rails once a week before you use the roller.
Here's the link:
http://www.petco.com/product/111974/Evercare-Mega-Cleaning-Roller-with-Extendable-Handle.aspx?CoreCat=OnSiteSearch
Chris